1. Field of the Invention
This invention relates to a cyclohexanecarboxylic acid ethyl ester derivative as a novel compound and a liquid crystal compositions containing the same.
2. Description of the Prior Art
Display elements utilizing liquid crystals have been broadly used for watches, electric calculators, etc. These liquid-crystalline display elements utilize the optical anisotropy and dielectric anisotropy of liquid-crystalline substances, and liquid-crystalline phases include nematic liquid-crystalline phase, smectic liquid-crystalline phase and cholesteric liquid-crystalline phase. Currently, display elements using nematic liquid crystals among those of the above phases have most widely been practically used. Such display elements include those of TN type (twisted nematic type), DS type (dynamic scattering type), guest-host type, DAP type, etc., and properties required for those of the respective types vary. As for liquid crystal compounds used for these display elements, there are preferred those which exhibit liquid-crystalline phases within a temperature range as broad as possible in the natural world, but at present there is no single compound which satisfies such a condition; hence several kinds of liquid crystal compounds and if required, non-liquid-crystalline compounds have been admixed for practical use. These compounds are required to be stable to moisture, light, heat, air, etc., and further it is preferred that the threshould voltage and saturation voltage required for driving display elements are as low as possible.
Still further, due to notable recent technical advance of liquid crystal display elements, liquid crystals having low viscosities have been required.
As a compound for such purposes, the following compound is known: ##STR3## (European patent publication No. 0104327, page 23, lines 13-14)
This compound has a m.p. of 97.degree. C. and a N-I point of 55.degree. C.
The object of the present invention is to provide a liquid crystal compound having a positive value of dielectric anisotropy and a low viscosity and being capable of extending the mesomorphic range of liquid crystal composition toward its lower region.